Logistics of the lease agreement when purchasing an occupied unit

[Mark S.]

I am in the process of purchasing a duplex with one side occupied. The current tenant has a lease which began in January, and terminates in 2021, so I'll be inheriting that lease. The seller sent me a copy of the tenant's lease, but the confusing part is that the lease is signed only by the tenant and dated within the last 2 weeks. Is the seller expecting me to sign the lease, and return it to him, to forward onto the tenant?

What is a typical sequence of events in regard to signing a new copy of the lease with the current tenant? (I know I'm responsible for the tenant's lease as-is. Do I even need to sign the new lease, or is it just for my records?) Does the seller deliver it to the tenant after I've signed it? Or do I deliver it upon closing, and then notify the tenant that rent should be paid to me, instead of the address mentioned in the lease?

I know that's a lot of questions. Any help is appreciated. (I also know that typically these questions would be directed at my agent, but we don't have agents involved on this deal.)